The non-binary code (NBC) or the lattice code (LC) has been the only possible channel code with the pulse amplitude modulation (PAM) signaling of modulation size greater than two for the physical layer network coding (PNC) over a decode-and-forward (DF) relaying channel. A major drawback with the NBC or LC however is its high computational complexity. In this letter, we present new modified high-o...
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We analyze the performance of a two hop channel state information (CSI)-assisted amplify-and-forward system, with co-channel interference at the relay. The system's outage probability and the average bit error rate (BER) in the presence of Rayleigh faded multiple interferers are investigated. We derive an exact expression for the outage probability and an accurate bound for the system's average BE...
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We propose to approximate the distribution of the sum of identically-distributed lognormal random variables by an Erlang distribution. The advantage of the proposed approximation over the lognormal and non-lognormal approximations proposed in the literature resides mainly in the fact that it results in simple closed-form expressions of the average bit-error-rate (BER) thus offering clear insights ...
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This paper focuses on how to determine an upper bound of maximum throughput from mesh clients to the Internet (or from the Internet to mesh clients) for multi-radio Wireless Mesh Networks (WMNs) under an interference-free assumption. In the case of the number of channels for assignment being high enough in a multi-radio WMN to meet the interference-free assumption, then the resulting solution can ...
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In this letter, we compare angle feedback and transmit antenna shuffling schemes for double space-time transmit diversity (DSTTD) systems with four transmit antennas and at least two receive antennas. We show that a DSTTD system with one bit of angle feedback does not provide better performance than the same system with one bit of transmit antenna shuffling. We also present a simplified general re...
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Directional antennas have shown to increase spatial reuse by allowing multiple transmitters and receivers to concurrently communicate using directional beams as long as they do not significantly interfere with each other. This appreciably increases average aggregate throughput of the network. Generally, for high throughput performance the directional MAC (Medium Access Control) protocols choose a ...
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In mobile phones, it is useful to know the most probable next location to make decisions about future actions. In this letter we compare three LZ based prediction algorithms. The originality of our work is that we make it in a cellular network, we separate the algorithms into two independent phases (tree updating and probability calculation), we have included Active LeZi in the study, and we evalu...
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In wireless sensor networks, geographic routing requires source nodes to be aware of the location information of sinks to send their data. Since sensor nodes have limited resources, providing the sink location service through low overhead is an important challenging issue. To address this issue, in this letter, we propose a simple sink location service scheme based on circle and line paths. In the...
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This letter presents an efficient tag collision arbitration protocol, viz., the Fast Tree Traversal Protocol (FTTP). It estimates the number of tags using maximum likelihood estimation and adjusts the splitting factor to reduce the identification delay. We show that our protocol effectively reduces the identification delay via the performance analysis and simulation results.
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As the analog front-end of an energy detector is highly susceptible to narrowband interference a modified energy detection scheme based on the Teager-Kaiser operator and high-pass filtering is considered. This letter analyzes the Teager-Kaiser operator output for an arbitrary number of narrowband band-pass signals having different amplitudes, center frequencies and bandwidths. The analysis reveals...
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In this letter we introduce a connection admission control (CAC) mechanism for IEEE 802.16 broadband wireless access Standard. Our scheme is based on bandwidth reservation concept and has been developed considering the problem of "busy hour" in communications traffic variation during a typical day. The proposed solution, which is compatible to the IEEE 802.16 Standard, provides higher priority to ...
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In this letter the transmission power and interference threshold constraints for a cognitive OFDM system are converted to a normalized capacity of each OFDM subchannel. A simple but very efficient algorithm is proposed to allocate bits of all subchannels, which always picks the bit with the least cost. Simulation results show the proposed algorithm can obtain optimum solution in most cases. The re...
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In this letter, we investigate the distribution of the phase component of the complex received signal observed in practical experiments using body area networks. Two phase distributions, the recently proposed κ-μ and η-μ probability densities, which together encompass the most widely used fading models, namely Semi-Gaussian, Rayleigh, Hoyt, Rice, and Nakagami-m, have be...
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A comprehensive study regarding the diversity and coding gains of fixed-gain amplify-and-forward dual-hop relaying systems with partial relay selection is performed. Our analysis allows for arbitrary independent Nakagami-m fading channels with distinct fading parameters among the links. It is shown that the diversity gain is determined by the minimum of the fading parameter pertaining to the selec...
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For multicarrier code-division multiple access (MC-CDMA) systems employing Alamouti's simple space-time block coding (STBC), a special relationship between two minimum mean-square error (MMSE) filter weight vectors is derived in which one filter is for detecting odd-indexed symbols and the other for even-indexed symbols. Using this relationship, a modified MSE cost function is presented and an imp...
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In multirate wireless networks, interference between higher and lower data rate links is a notorious factor against performance improvement. We include the interference calculation to derive useful properties in achieving the maximum network throughput, and develop a linear-time channel assignment algorithm accordingly. Through extensive simulations, we show that the proposed algorithm much improv...
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Simple expressions for the symbol error rate of some coherent and noncoherent modulation schemes with dual maximal ratio combining operating in identically distributed correlated Nakagami-q fading are derived. The new expressions are derived based on a decorrelation transformation applied to the correlated branches. New expressions are given as both closed-form and finite range single integrals of...
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Various authentication solutions are to be considered and tested for possible adoption in space Telecommand system due to the accessibility of space wireless channel. Most of the solutions proposed previously are designed oblivious of the difference in protocol misbehavior due to attacks and due to normal interference in space channel. We propose an innovative misbehavior detection algorithm for C...
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Practical random network coding based schemes for multicast include a header in each packet that records the transformation between the sources and the terminal. The header introduces an overhead that can be significant in certain scenarios. In previous work, parity check matrices of error control codes along with error decoding were used to reduce this overhead. In this work we propose novel pack...
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We show that polar codes asymptotically achieve the whole capacity-equivocation region for the wiretap channel when the wiretapper's channel is degraded with respect to the main channel, and the weak secrecy notion is used. Our coding scheme also achieves the capacity of the physically degraded receiver-orthogonal relay channel. We show simulation results for moderate block length for the binary e...
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The remarkable results of Fountain codes over the binary erasure channel (BEC) have motivated research on their practical implementation over noisy channels. Trapping sets are a phenomenon of great practical importance for certain graph codes on noisy channels. Although trapping sets have been extensively studied for low-density parity-check (LDPC) codes, to the best of our knowledge they have nev...
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